Sheet metal panel and method of making same



Dec. 25, 1952 H. E. SWITZGABLE, JR 3,079,196

SHEET METAL PANEL AND METHOD OF MAKING SAME Filed April 14, 1960 J Isauna/v m 22 Agra/44 m FOAM com INVENTOR. HARULD E- SW1 TZ EABLEJB /ZJ/MUnited States Patent Ofilice 3,070,196 Patented Dec. 25, 1962 3,070,196SHEET METAL PANEL AND METHOD OF MAKING SAME Harold E. Switzgable, Jr.,21 Adams Drive, Princeton, NJ. Filed Apr. 14, 1960, Ser. No. 22,214 7Claims. (Cl. 189-34) This invention relates to sheet metal panelconstructions, and methods of making same. The invention is particularlyuseful in the constniction of door panels, such as for sectional steeldoors, and also in the construction of buildings, partitions and variousother enclosures.

It is an object of the invention to provide a sheet metal panelconstruction which consists of a minimum number of parts each of whichcan be conveniently and economically formed.

It is another object of this invention to provide a novel and economicalmethod of constructing an attractive-appearing and rigid sheet metalpanel which is also efiective for thermal insulation purposes.

It is a further object of this invention to provide a sheet metal panelso constructed as to have a large measure of rigidity and of resistanceto twisting or other deformations.

It is still a further object to provide a sheet metal panel having afinished appearance on all sides.

It is yet another object to provide a sheet metal panel adapted andconstructed to be used where thermal insulation is desired.

. The foregoing and other objects of the invention are achieved by aconstruction, and a method of construction, wherein two sheets of metalare formed to provide a shallow box-like structure. One of the sheets isformed to provide the top and two opposite sides of the box and toprovide flanges extending from the sides towards each other in a planeparallel with the top. The other sheet of metal is similarly termed butis dimensioned to slide into the first one and to thereby con stitutethe bottom and two ends of the box-like structure. The interior of thebox-like structure may be filled with a thermal insulation material.According to a preferred construction and method of construction, afoaming plastic liquid is applied to an inner surface of one of theformed metal sheets and is allowed to foam and solidify in place insidethe assembled formed sheets toform a bonded rigid panel structure.

These and other objects and aspects of the invention are described ingreater detail in connection with the appended drawings, wherein:

FIGURE 1 is a perspective view, with portions cut away, of a sheet metalpanel constructed in accordance with the teachings of this invention;

FIGURE 2 is a longitudinal sectional view of the panel shown in FIGURE1, and taken on the line 2-2 of FIGURE 3;

FIGURE 3 is a transverse sectional view of the panel of FIGURE 1 andtaken on the line 33 of FEGURE 2; and

FIGURE 4 is a perspective view of two sheet metal elements which may besubstituted for one of the formed sheet metal elements in the embodimentof FIGURES 1 through 3 for the purpose of providing greater rigidity,and providing localized strength for the attachment of hardware or thelike.

Reference will now be made in greater detail to FIG- URES 1 through 3 ofthe drawings which show a sheet metal panel that is particularly usefulin the construction of rolling overhead garage doors or the like. Theboxlike sheet metal panel is constructed of a first sheet of metal whichis formed to provide the top and two sides of the box, and a secondsheet of metal 11 which is formed to provide the bottom and two ends ofthe box. The sheet of metal 10 has a major flat portion 12 con stitutingthe top of the box, and has two opposite edges formed into alap-joint-shaped side 14 and a complimentary lap-joint-shaped side 16.It will he understood that while the sides 14 and 16 are shown as beinglap joint shaped, the sides may be straight, or may be shaped to provideany other kind of joint such as a tongue-and-groove joint or a scarfjoint. The metal sheet 10 is also additionally formed to provide flanges18 and 20 extending from the bottoms of the sides 14 and 16,respectively, toward each other and parallel the surface of the topportion 12. It is thus far apparent that the sheet of metal 10 isformed, as by means of a brake, to provide a unitary elementconstituting the top 12, and the sides 14 and 16 of a box-likestructure, and also to form the flanges 18 and 29.

The second sheet of metal 11 used in the construction of the box-likestructure is similarly formed to provide a major intermediate portion orbottom 22, and ends 24 and 26 of the box-like structure. The metal sheet11 is additionally formed to provide flanges 2-8 and 30 extending fromthe upper edges of the ends 24 and 26, respectively, toward each otherand parallel with the bottom portion 22 of the sheet. The metal sheet 11is formed to provide the bottom 22, the ends 24 and 26, and the flanges28 and 3%), the various portions of the metal sheet 11 being dimensionedso that the formed sheet 11 can be assembled into the position shown inthe drawing by sliding the formed metal sheet 11 into and inside theformed metal sheet 10.

When the sheet metal panel of FIGURES 1 through 3 is to be used in anenvironment where it is desirable to provide thermal insulation, a battof insulating material is dimensioned and positioned in the formed metalsheet 11 prior to sliding the formed metal sheet 11 inside the formedmetal sheet It). The oatt of insulating material may comprise any of thepulp or textile or noncombustible fibers, or may comprise a block ofsolid foamed plastic. Alternatively, the batt of insulating material maybe constituted by a honeycomb core having dimensions to fill theinterior space.

It will be understood that a good measure of thermal insulation isprovided by the box-like panel construction even though the interior isnot filled with insulating material. This results from the fact that thebox-like construction encloses a dead air space. The construction isparticularly effective for this purpose when the sides 14 and '16 arestraight and not lap joint shaped, or when the openings 32 are closed byany suitable means.

The formed metal sheets 11? and 11 may be fastened in the assembledposition shown in the drawing by a suitable means, such as by applyingan adhesive to portions of the flanges 18, 2t), 28 and 30, or byemploying sheet metal screws or blind rivets connecting the flanges tothe contiguous surfaces of the other formed metal sheet, or by employingthrough bolts such as in connection with the attachment of hardware tothe panel.

A preferred construction, and method of construction, will now bedescribed. A foaming plastic liquid is applied to the major surface ofone of the formed metal sheets it) or 11. This is preferably done beforethe bottom formed sheet 11 is slid into the top formed sheet 10, orsimultaneously with the step of sliding the formed sheet 11 into the topsheet 10. The foaming plastic liquid is applied by a pumping or sprayingapparatus including a mixing valve which mixes the two ingredientsnecessary to initiate the foaming action. The foaming plastic should beone, such as polyurethane or epoxy, which will adhere to the formedmetal sheets 10 and 11.

After the foaming plastic liquid is applied to an interior surface ofone of the formed metal sheets, the sheets are maintained in thefinally-desired assembled relationship while the plastic liquid foamsand fills the interior space. After this occurs, the foam solidifies andbonds to the formed metal sheets and 11 so that they are permanentlyfixed together as a panel. No other fastening means are required. Itwill be noted that the formed sheets 10 and 11 are so shaped that theycan be disassembled only by a sliding motion. This motion is completelyprevented by the bonded plastic foam in the interior of the panel.Therefore, the flanges 18, 20, and 28, 30 need be made to extend fromthe respective sides and ends a distance just suflicient to provide thedesired rigidity and the necessary bearing surfaces for locating the twoformed sheets relative to each other.

In addition to bonding the formed metal sheets against slidingdisassembly, the foamed-in-place plastic also acts as the core of asandwich construction of which the top and bottom metal surfaces 12 and22 constitute the exterior skins. This sandwich construction gives greatstrength against denting of the panel, as well as strength againsttwisting, bending and other deformation. Still another advantage of thefOamed-inplace plastic core is the thermal insulation provided thereby,which makes the resulting panel especially desirable for incorporationin overhead garage doors.

When the sheet metal panel has a great length in the direction of thesectional view of FIGURE 2, and considerable rigidity is desired, thesheet metal panel may be constructed to include a plurality of formedmetal sheets 36 and 38 as shown in FIGURE 4, in place of the singleformed metal sheet 11 shown in FIGURES 1 through 3. When the membersshown in FIGURE 4 are employed, the flanges 40 and 42 thereon provideadditional rigidity for the assembled panel, and provide additionalmetal as a foundation for the connection of hardware or the like to thepanel.

It is thus apparent that according to the teachings of this inventionthere is provided a sheet metal panel which is very rigid, is neat inappearance, provides thermal insulation and is simple and economical tofabricate.

What is claimed is:

l. A construction panel comprising a hollow, shallow, box-like structureconstructed of a first sheet of metal formed to provide the top and twoopposite sides of the box and to provide flanges extending from thesides toward each other in a plane parallel with the top, and a secondsheet of metal formed to provide the bottom and two opposite ends of thebox and to provide flanges extending from the ends toward each other ina plane parallel with the bottom, said second formed sheet beingdimensioned to slide into said first formed sheet.

2. A construction panel comprising a hollow, shallow, box-like structureconstructed of a first sheet of metal formed to provide the top and twoopposite sides of the box and to provide flanges extending from thesides toward each other in a plane parallel with the top, a second sheetof metal formed to provide the bottom and two opposite ends of the boxand to provide flanges extending from the ends toward each other in aplane parallel with the bottom, said second formed sheet beingdimensioned to slide into said first formed sheet, and means to fastensaid two formed sheets together in the assembled position.

3. A construction panel according to claim 2 wherein said fasteningmeans is located to secure the flanges of at least one of said formedsheets to the contiguous surface of the other of said formed sheets.

4. A construction panel comprising a hollow, shallow, box-like structureconstructed of a first sheet of metal formed to provide the top and twoopposite sides of the box and to provide flanges extending from the sidetoward each other in a plane parallel with the top, a second sheet ofmetal formed to provide the bottom and two opposite ends of the box andto provide flanges extending from the ends toward each other in a planeparallel with the bottom, said second formed sheet being dimensioned toslide into said first formed sheet, and a bad of insulating materialdimensioned to fit inside said second formed sheet and to be slidtherewith into said first formed sheet.

5. A construction panel comprising a hollow, shallow, box-like structureconstructed of a first sheet of metal formed to provide the top and twoopposite sides of the box and to provide flanges extending from thesides toward each other in a plane parallel with the top, a second sheetof metal formed to provide the bottom and two opposite ends of the boxand to provide flanges extending from the ends toward each other in aplane parallel with the bottom, said second formed sheet beingdimensioned to slide into said first formed sheet, and a foamedinplaceplastic occupying the interior space of said box-like structure.

6. A construction panel as defined in claim 1 wherein a plurality ofsaid second formed sheets are employed and" V are dimensioned to slideinto said one first formed sheet to form a box-like structure having aplurality of chamhers.

7. A construction panel comprising a hollow, shallow, box-like structureconstructed of a first sheet of metal formed to provide the top and twoopposite sides of the box and to provide flanges extending from thesides toward each other in a plane parallel with the top, said oppositesidesof the box being formed to provide complementary joint-shapedsurfaces, and a second sheet of metal formed to provide the bottom andtwo opposite ends of the box and to provide flanges extending from theends toward each other in a plane parallel with the bottom, said secondformed sheet being dimensioned to slide inside said first formed sheet.

References Cited in the file of this patent UNITED STATES PATENTS1,797,706 Winslow Mar. 24, 1931 2,730,210 McLaughlin Jan. 10, 19562,744,042 Pace May 1, 1956 2,951,781 Toegel Sept. 6, 1960 FOREIGNPATENTS 664,562 Great Britain Jan. 9, 1952

